Crude oil or petroleum consists of a mixture of different hydrocarbons. The most commonly found hydrocarbon molecules in crude oil are alkanes (linear or branched), cycloalkanes, aromatic hydrocarbons, or more complicated chemicals like asphaltenes.
Oil sands, which may also be referred to as tar sands, are a type of unconventional petroleum deposit. In the Athabasca region of northern Alberta lie the Athabasca oil sand deposits, one of the largest reserves of oil in the world. The oil sands consist essentially of a matrix of bitumen, sand, water and clay which has a very high viscosity and is therefore practically immobile. The bitumen may be some times defined as a form of extra heavy oil and is extremely difficult to extract.
Methods used to separate the bitumen from the sand require significant energy, chemicals and/or water. In certain circumstances, the sands can be extracted by strip mining, or the bitumen can be made to flow into wells by in situ techniques, which reduce the viscosity by injecting steam, solvents, and/or hot air into the sands.
Presently, SAGD, (steam assisted gravity drainage), is most commonly used to extract the bitumen from the deposits below 400 m depth. The SAGD process requires vast amounts of water and natural gas and has, therefore, a large environmental impact.
Once separated from the sand, lighter oils and hydrocarbons can be obtained from crude oil and heavier hydrocarbons through cracking processes involving distillation of crude oils in processing plants. Cracking, or refining, is the overall reduction of lengths of hydrocarbon chains, usually in alkanes.
Methods used to distill and process lighter from heavier hydrocarbons require significant use of energy and processing infrastructure. Raw crude hydrocarbons are extracted from deposits, piped or delivered in some other manner to distillation plants, and submitted to cracking processes known as refining. Heavier oils, particularly bitumen, may need to be mixed with solvents in order to facilitate delivery.
Ultrasonics has been attempted for in situ oil sand extraction processes previously but only using water as an ultrasonic media. Ultrasonics requires some media for sound to travel through in order for sound to come into contact with oil sand. Using water as sonic media has not proven economically viable for in situ bitumen recovery since the water cannot penetrate very far into the oil sand matrix due to the immiscible nature of oil and water.
U.S. Pat. No. 4,054,506 provides for a method of removing bitumen from oil sand for subsequent recovery of the bitumen. The method disclosed in this patent application, however, utilizes an above-ground vessel into which mined oil sand, broken down into small segments, is placed. The method disclosed in this patent consists of contacting oil sand matrix with an excess of solvent in which the bitumen is soluble. The contacting is performed within a vessel, and simultaneously the solvent is being stirred and ultrasonic energy is being applied. Both stirring and breaking down the oil sand into small segments incorporates air into the ultrasonic media and greatly detracts from the effectiveness of using ultrasonics as a separation process. That is, the extraction of bitumen from oil sand occurs after the oil sands are mined to the surface, broken down into quarter (¼) inch segments, and stirred within a vessel while ultrasonics are applied. Usually these methods require large expensive machinery or vessels and expose the environment and humans to toxic chemicals. Because of the incorporation of air into the ultrasonic media, the process has a reduced effectiveness.
US Pat. Publ. No. 20080139418 (US '418) discloses an in situ method for extracting bitumen from sand consisting of adding a release agent directly to the oil sand, followed by the use of an alkaline water-based extraction liquid for washing the loosened bitumen which is then pumped to the surface. Ultrasonic transducers are used within a tank (i.e. ex situ), and only to separate remaining sand bound to bitumen. In summary, the extraction method of US '418 uses water and ultrasonic transducers ex situ.
The abstract of Russian Patent No. 2,241,829 (Orlov at al.) describes a method for treating face-adjacent bed areas. The method consists of replacing the well liquid with hydrocarbon liquid (a water-less oil), pumping and partially pushing a treating compound into the bed, the level of the hydrocarbon liquid in the well is lowered down to mark at which bed pressure is 1.52 to 2 times greater than the face pressure. Under such conditions implosive treatment is performed. Then an ultrasound emitter is lowered and ultrasound treatment of face-adjacent bed area is performed. The method disclosed by Orlov at al, however, does not relate to in situ methods of extracting and separating hydrocarbons from a hydrocarbon matrix in an oil formation, of relining heavy crude oil in an oil formation, or of processing an oil formation. Furthermore, the method of Orlov et al. requires implosive treatment of the oil well, which increases the threat of explosions or blowouts. Accordingly, what is needed are in situ methods of extracting and separating hydrocarbons from a hydrocarbon matrix in an oil formation, of refining heavy crude oil or processing an oil formation that can be carried out at low pressure by pouring or disposing a treating compound into a well without the necessity of high-pressure injection pumps.
Needed are methods for separating, extracting and refining hydrocarbons from a hydrocarbon matrix, such as oil sand without addition of a polar liquid such as water, or with the addition of relatively small amounts of polar liquids. Also needed are methods for separating, refining and extracting hydrocarbons from oil formations in situ, that is, without mining or removal of the oil from the subsurface, and without the addition of a polar liquid like water, or adding relatively small amounts of polar liquids. What is also needed is a non-polar ultrasonic media which can be used for separating, extracting or refining of hydrocarbons.